Page:Popular Science Monthly Volume 2.djvu/115

Dr. Livingstone from the appearance of the telegram? You assumed over and over again the existence of uniformity in Nature. That the newspapers had behaved as they generally do in regard to telegraphic messages; that the clerks had followed the known laws of the action of clerks; that electricity had behaved in the cable exactly as it behaves in the laboratory; that the actions of Mr. Stanley were related to his motives by the same uniformities that affect the actions of other men; that Dr. Livingstone's handwriting conformed to the curious rule by which an ordinary man's handwriting may be recognized as having persistent characteristics even at different periods of his life. But you had a right to be much more sure about some of these inferences than about others. The law of electricity was known with practical exactness, and the conclusions derived from it were the surest things of all—the law about the handwriting, belonging to a portion of physiology which is unconnected with consciousness, was known with less, but still with considerable accuracy. But the laws of human action in which consciousness is concerned are still so far from being completely analyzed and reduced to an exact form, that the inferences which you made by their help were felt to have only a provisional force. It is possible that by-and-by, when psychology has made enormous advances and become an exact science, we may be able to give to testimony the sort of weight which we give to the inferences of physical science. It will then be possible to conceive a case which will show how completely the whole process of inference depends on our assumption of uniformity. Suppose that testimony, having reached the ideal force I have imagined, were to assert that a certain river runs up-hill? You could infer nothing at all. The arm of inference would be paralyzed, and the sword of truth broken in its grasp; and reason could only sit down and wait until recovery restored her limb, and further experience gave her new weapons.—Advance Sheets from Macmillan.

SKETCH OF PROFESSOR TYNDALL.

THE Tyndall or Tyndale family emerged into history about the same time as the American Continent. The first of whom we hear was William Tyndale, a contemporary of Columbus, and who was just of age when this country was discovered. It was the epoch of intellectual awakening in Europe, and the impulse was felt equally in geographical exploration and in religious reform. Tyndale took to the latter, and translated the Bible into English for the people. But he found worse navigation on the theological sea than Columbus en-